Hitherto, pneumatically operated pumps for use in mining applications have generally included a sump into which water flows for subsequent propulsion therefrom by an impeller or double acting diaphragm which is driven by compressed air. It is standard practice to leave such pumps running continuously to ensure a substantially water free mining environment at all times. However, such a mode of operation leads to high levels of wear and failure, especially when water is not passing into the sump.
Automatic control systems and valves have been contemplated, however, these involve complicated switching systems which due to their intricate nature are not suitably durable for use in a mining environment.
Moreover, to leave such pump running dry is highly inefficient since each pump requires 50 to 100 cubic feet of compressed air per minute, the large majority of which is wasted. These pumps are also bulky and cumbersome and as such difficult to move in the confined spaces in a mine.
Prior art pumps and the valve systems used therein are generally expensive to produce, require a relatively large number of moving parts, and incorporate a large number of aluminum components which are readily corroded by the alkaline or acidic waters often encountered.